Gotenna mesh replaceable battery?


#21

Like spacecraft, computers in cars are special cases. They are told to go stand in the corner and we’ll get back to you. Not connected to the internet or anywhere else, much, just keep reporting back. If connecting to the present day, every day, it’s a bit steeper slope in terms of keeping up with the Joneses.


#22

I wouldn’t classify the goTenna as a computer. It’s more of a micro controller. My point is that it should have no problem lasting beyond the 5 year mark. The battery is the weak link. To look at it from a Ham radio point of view, VHF / UHF repeaters are not replaced every 5 years. There are new HT’s every year or so but the repeater system they work on is the same. My Yaesu Vx-7r is roughly 16 years old and it still works. If I had to guess my local repeater in Philadelphia is probably 20+ years old. They’ve added other modes to the site but the analog 144 / 440 is still there. Without a mesh network with (always on) relays in place the goTenna’s are not much better that a few frs radios. With a replaceable battery or external power port I could keep my mesh relays up for a very long time (10 years).


#23

That’s understandable, but for most users in most situations, the battery configuration serves very well and avoids a host of other issues the average consumer may not want to deal with. That maximizes the number of users on the network, on average.

The present design really wasn’t made with the intent of use for stationary nodes except as a very secondary use. It’s optimized for portability and daily use. So that’s also something to keep in mind. I would eventually expect a version that’s optimized for relay use, but there’s only so many resources, so much time, and so much capital. Give it time. Until then, we must improvise.

Speaking of hams, they often engage in modification of their equipment. It’s a little tricky to get apart, but a pretty easy fix then, just hook up the battery holder of your dreams. Don’t even need a ham ticket to do that, just some handyperson skills.


#24

All things with “no user serviceable parts” are totally user serviceable if one is willing to crack it open. A battery replacement/swap is way mo easier than adding an antenna connector.


#25

While it’s “doable” it’s not very clean nor is it easy. I’ve done it for one of my MOAN relays. This is not something the average users is going to put up with. When the battery dies they’ll just throw it out. Not the way to build or sustain a mesh network.


#26

Which is why I said,[quote=“dennilee, post:24, topic:3703”]
if one is willing
[/quote]. I have found that the sharp blow to the side cracks the case open cleanly,( take care with the switch & USB connector), and that

the battery is connected with real wires into through hole solder points. If one wishes to tinker this is an easy starting point. My “experimental unit” has 2+ & 2- connections so that cells can be hot swapped.


#27

Ordinarily, when people draw parallels between the goTenna Mesh and cell phones, it’s rather tendentious and off-putting, given that most such comparisons miss their mark.

When it comes to batteries, though, I think it’s valid to point out that what is widely accepted with cell phones, the integral, rechargeable battery, seems to be a pretty safe bet for consumer acceptance as implemented in the goTenna Mesh.


#28

The difference is phones come and go. But the network there on continues to grow.


#29

On one hand, goTenna is much kinder to its battery simply due to the fact that full charge voltage is the proper 4.2 volts, not the 4.3-4.4 volts that most phones and laptops go to. However, the arguments used against replaceable batteries are starting to sound weak to me. Is a decent rubber seal that hard to come by nowadays?

A few years ago, some ruggedized phones were available on the market that could take a beating but still had a removable battery. Even the Galaxy S5 had a removable battery with a fairly tight seal. My Garmin eTrex takes a pair of AA batteries but is virtually waterproof and uses a tool-free battery cover.

When it comes to packaging, my Galaxy S3 is as thin as an iPhone 5s, but has an easily removable back cover for access to a battery, SIM card, and MicroSD slot.

I’m not trying to come across demeaning, I simply want to know why a device can’t be made strong and weathertight while retaining a modular battery.


#30

It would be pretty cool to have a gotenna with a replaceable 18650 battery, with a screw on cap on the bottom.


#31

It would also be cool if that same screw cap could be replaced with one that allowed an external power connection. Giving you the option to use the battery cap / holder or remove that and use the power connection cap.


#32

Something like this. The long one is the battery holder. The small one would be the power connection cap.


#33

Of course it can be. And it will be more expensive, heavier, bigger…

Then there’s the motivation to do this…because one day the battery will go paws up? In which case, those worried about milking the last bit of ROI out of their (by then) creaky old GTM can always do a battery hack then.

What’s still missing is a circuit to maintain power. Maybe it can be done by plugging the original USB port into power while the battery is replaced? Or maybe put a cap to maintain power where the original internal battery was? Unless you really want to reload all the data when you disconnect the power when replacing the battery…

I see the point of doing this in certain situations. I just don’t see the drive to impose this on everyone by making the peculiar needs of some dictate design for all. This is when I usually expect to get my tools and soldering iron out and just DIY things. Besides, wouldn’t a new design also suggest a replacement of your existing inventory? Such an extensive redesign would seem to suggest that the new “return to previous state” power button be included and that’s a far more useful and desirable feature in my eyes and it won’t change the form factor at all. I don’t see how that recoups you from your concerns about not fully depreciating your present investment if that was your starting concern.


#34

Eventually a hardware revision will need to be made, such as for previous state after power, which is when all the other hardware changes will be made. Whether or not that makes people retire their current devices early is up to them, although I’d prefer only relay units be replaced with state-saving models. For me personally, it would take a game-changing revision for me to buy any more units, such as multi-day battery life and/or standalone capabilities.

Looking back at the pictures I took when I built my goTennaMod, it looks like the existing case could accommodate being made to separate upper half from bottom half and be held together with a screw, allowing for easy access to the internals while retaining existing specs. Instead of the battery being soldered directly to the board, use a JST connector. This would also allow goTenna to easily sell two variants. One could be a dedicated relay that ships with a capacitor pack so thermal concerns more or less go right out the window, the other being the stock goTenna Mesh with lithium ion battery.

As for data retention when the battery is removed, the app automatically provisions the device when connected, so I don’t think that is an issue. I don’t recall having to re-pair my Mod unit after changing the battery pack, and I didn’t take any care to retain power the whole time the unit was apart. My board sat for hours with no battery connected.

Even as a DIY person, wouldn’t it be nice to be able to simply remove a screw and have access to the internals rather than going through the headache of splitting the welded case open, potentially destroying it in the process?


#35

Why do you need a circuit to maintain power?


#36

I suspect that the case being made this way is not much about the battery at all and more about waterproofing and case strength. The FCC requires that the antenna not be user-exchangeable so that the unit can’t be easily modified to exceed the max ERP. I suspect that the sealed case is related to the same general goal of discouraging user modification through discouraging easy access, while keeping moisture out. It’s the simplest, cheapest solution to meeting multiple design requirements. Once you put a door in it, accomplishing the same goals is going to be more expensive and will create the need to rethink the way the case is made.

I’m pretty sure that it’s more than just a matter of adding a screw.


#37

My bad if I assumed the memory was in part volatile. If there’s no need for power maintenance, that solves just one of the many issues raised by making provision for an exchangeable battery.

For instance, the battery chemistry and specs would need to be conducive to the existing charging circuit with whatever battery you adopt or something suitable for the new battery would need to be added. I’m not an engineer, so unless there is a clear solution offered to such obvious issues, I’ve got to assume that they remain relevant.

Then there’s the human interface aspect. Put in something that takes AA or AAA batteries and the some users start sticking anything that fits in, quite often something cheap. Then the unit doesn’t last as long as the spec indicates and people start saying the battery should be bigger and the cycle continues. With a single, known quality battery in all units, this aspect of determining the source of user frustration is simplified to either the battery is working to spec or it’s not.

LiPo battery chemistry is also generally regarded as better for the environment than that of other rechargeables. This may be another factor in play here, depending on what the assumed form factor and availability in standard consumer packaging may be for the rechargeables you have in mind. If it’s going to be typical AA or AAA, then there’s the issue of someone putting non-rechargeables in and causing things to go awry unless a switch is added to turn off the charge circuit. Then you hope that people use it.


#38

New molds would definitely be necessary, but only to facilitate rotating the seam 90 degrees. The bottom piece, with both aluminum vaneers, would slide up into the top piece as opposed to the front and rear halves being welded together.

Inside the top case, mold in a divider that holds the board in place. This divider would continue out the bottom of the top half and have threads for a screw to thread into. The battery would then have a sticky pad (like it does currently) to adhere to this divider. The bottom half of the case would slide up into the top half and rest against a rubber seal, held tight by a screw in between the aluminum vaneers on the bottom edge. Very similar form factor, still pretty watertight, but easily opened. As far as the FCC is concerned, this design should still satisfy their requirements as the antenna is integral to the board and it has no connector.


#39

Having some knowledge of how the plastic industry operates due to being a model railroader, when you say “new molds” it often comes down to that cost being the predominant factor in whether a model gets produced or not. With enough demand, not a problem, but this cost is far from insubstantial.

Two big factors here. I would not expect goTenna to produce both a relay oriented version and a consumer version of a exchangeable battery system unless they could make the case fit both. Cost of molds is part of that.

The other is why the push to modify the hardware, when you can easily use an outboard battery pack to supply however much power than you’ll likely ever need? Voltaic makes nice, relatively compact versions. The Chinese offer lots of interesting units, too. Using one of these allows for extra capacity when needed, plus instant conversion back to original form factor by simply unplugging. Best of both worlds and already available.


#40

Sonnet looks to have a battery connection that would allow easier replacement. Their case is also welded but looks like it would be easier to work with once cracked open. Still not ideal, but a nice 3d case could be made to fit it.

Sonnet